Investigators say what little evidence they have to work with, including the loss of communications, suggests the Boeing 777 was deliberately diverted thousands of kilometres from its scheduled route.

The search was narrowed last month after a series of acoustic pings thought to be from the plane's black box recorders were heard near where analysis of satellite data put its last location, some 1,600 km (1,000 miles) off the northwest coast of Australia.

"The Australian Transport Safety Bureau (ATSB) has advised that the search in the vicinity of the acoustic detections can now be considered complete and, in its professional judgment, the area can now be discounted as the final resting place of MH370," the agency in charge of the search said in a statement.

ATSB chief Martin Dolan told Reuters he expected the team to take two to three weeks to reassess and re-analyze the data, although he was "confident" that the final resting place of the aircraft was the Indian Ocean.

"We don't know what those pings were," Dolan said over the phone. "We are still analyzing those signals to understand them better."

Chinese Premier Li Keqiang urged Malaysian Prime Minister Najib Razak on Thursday to come up with a new search plan.

"We hope the Malaysian side can play a leading and coordinating role and quickly put in a place a new search plan to find where the plane came down and seriously develop the investigation," Li said during Najib's six-day visit to China, according to the official Xinhua news agency.